ortho compound passing over with the steam. It
crystallizes in orange-red needles which melt at 82.5-83deg C. On reduction
with zinc dust in dilute sal-ammoniac solution, it yields ortho-aminophenol
and aniline. Meta-oxyazobenzene, C_6H_5N:N(1)C_6H_4.OH(3), was obtained in
1903 by P. Jacobson (_Ber._, 1903, 36, p. 4093) by condensing
ortho-anisidine with diazo benzene, the resulting compound being then
diazotized and reduced by alcohol to benzene-azo-meta-anisole, from which
meta-oxyazobenzene was obtained by hydrolysis with aluminium chloride. It
melts at 112-114deg C. and is easily reduced to the corresponding hydrazo
compound.

_Diazo-Amines._--The diazo-amines, R.N:N.NHR_1, are obtained by the action
of primary amines on diazonium salts; by the action of nitrous acid on a
free primary amine, an iso-diazohydroxide being formed as an intermediate
product which then condenses with the amine; and by the action of
nitrosamines on primary amines. They are crystalline solids, usually of a
yellow colour, which do not unite with acids; they are readily converted
into amino-azo compounds (see above) and are decomposed by the concentrated
halogen acids, yielding haloid benzenes, nitrogen and an amine. Acid
anhydrides replace the imino-hydrogen atom by acidyl radicals, and boiling
with water converts them into phenols. They combine with phenyl isocyanate
to form urea derivatives (H. Goldschmidt, _Ber._, 1888, 21, p. 2578), and
on reduction with zinc dust (preferably in alcoholic acetic acid solution)
they yield usually a hydrazine and an amine. Diazoamino benzene,
C_6H_5.N:N.NHC_6H_5, was first obtained by P. Griess (_Ann._, 1862, 121, p.
258). It crystallizes in yellow laminae, which melt at 96deg C. and explode
at slightly higher temperatures. It is readily soluble in alcohol, ether
and benzene.

_Diazoimino benzene_, C_6H_5N_3, is also known. It may be prepared by the
action of ammonia on diazobenzene perbromide; by the action of
hydroxylamine on a diazonium sulphate (K. Heumann and L. Oeconomides,
_Ber._, 1887, 20, p. 372); and by the action of phenylhydrazine on a
diazonium sulphate. It is a yellow oil which boils at 59deg C. (12 mm.),
and possesses a stupefying odour. It explodes when heated. Hydrochloric
acid converts it into chloraniline, nitrogen being eliminated; whilst
boiling sulphuric acid converts it into aminophenol.

_Azoxy Compounds_, R.[=N.O.N].R', are usually yellow or red crystalline
solids which result fr